The regulation of intracellular calcium is a key element in the transduction of signals into and within cells. Cellular responses to growth factors, neurotransmitters, hormones and a variety of other signal molecules are initiated through calcium-dependent processes. The importance of calcium ion as a second messenger is emphasised by many different mechanisms which work together to maintain calcium homeostasis. Changes in intracellular free calcium ion concentration represent the most wide-spread and important signalling event for regulating a plethora of cellular responses. A widespread route for calcium ion entry into the cell is through store-operated channels (SOCs), i.e. many cell types employ store-operated calcium ion entry as their principal pathway for calcium ion influx. This mechanism is engaged following calcium ion release from stores, where the depleted stores lead to activation of calcium release-activated calcium (CRAC) channels.
CRAC channels, a subfamily of store-operated channels, are activated by the release of calcium from intracellular stores, particularly from the endoplasmic reticulum (ER). These channels are key factors in the regulation of a wide range of cellular function, including muscle contraction, protein and fluid secretion and control over cell growth and proliferation and hence play an essential role in various diseases such as immune disorders and allergic responses. Among several biophysically distinct store-operated currents the best characterized and most calcium ion selective one is the CRAC current. Thus, CRAC channels mediate essential functions from secretion to gene expression and cell growth and form a network essential for the activation of immune cells that establish the adaptive immune response. Recently two proteins, stromal interaction molecule (STIM1) and CRAC Modulator 1 (CRACM1 or Orai1), have been identified as the essential components that fully reconstitute and amplify CRAC currents in heterologous expression systems with a similar biophysical fingerprint. In mammals, there exist several homologs of these proteins: STIM1 and STIM2 in the endoplasmic reticulum and CRACM1, CRACM2, and CRACM3 in the plasma membrane.
CRAC currents were initially discovered in lymphocytes and mast cells, and at the same time have been characterized in various cell lines such as S2 drosophila, DT40 B cells, hepatocytes, dendritic, megakaryotic, and Madin-Darby canine kidney cells. In lymphocytes and in mast cells, activation through antigen or Fc receptors initiates the release of calcium ion from intracellular stores caused by the second messenger inositol (1,4,5)-triphosphate (Ins(1,4,5)P3), which in turn leads to calcium ion influx through CRAC channels in the plasma membrane. Store-operated Ca2+ currents characterized in smooth muscle, A431 epidermal cells, endothelial cells from various tissues, and prostate cancer cell lines show altered biophysical characteristics suggesting a distinct molecular origin.
For example, calcium ion influx across the cell membrane is important in lymphocyte activation and adaptive immune responses. [ca2−]-oscillations triggered through stimulation of the TCR (T-cell antigen receptor) have been demonstrated to be prominent, and appear to involve only a single calcium ion influx pathway, the store-operated CRAC channel. See, e.g., Lewis “Calcium signalling mechanisms in T lymphocytes,” Annu. Rev. Immunol. 19, (2001), 497-521; Feske et al. “Ca++ calcineurin signalling in cells of the immune system,” Biochem. Biophys. Res. Commun. 311, (2003), 1117-1132; Hogan et al. “Transcriptional regulation by calcium, calcineurin, and NFAT,” Genes Dev. 17, (2003) 2205-2232.
It is well established now that intracellular calcium plays an important role in various cellular functions, and that its concentration is regulated by calcium ion influx through calcium channels on the cell membrane. Calcium ion channels, which are located in the nervous, endocrine, cardiovascular, and skeletal systems and are modulated by membrane potential, are called voltage-operated Ca2− (VOC) channels. These channels are classified into L, N, P, Q, R, and T subtypes. Excessive Ca2− influx through the VOC channels causes hypertension and brain dysfunction In contrast, calcium ion channels on inflammatory cells, including lymphocytes, mast cells, and neutrophils, can be activated regardless of their membrane potential. This type of calcium ion channel has been reported to act in the crisis and exacerbation of inflammation and autoimmune diseases. In the T cells, it has been reported that the early stages of activation consist of pre- and post-Ca2+ events. The stimulation of T cell receptors induces pre-Ca2+ events, including the generation of IP3, followed by the release of Ca2+ from the endoplasmic reticulum (ER). In post-Ca2+ events, depletion of Ca2+ in the ER induces the activation of CRAC channels, and capacitative Ca2− influx through the CRAC channel sustains high intracellular Ca2− concentration ([Ca2+]i). This prolonged high [Ca2+]i activates cytosolic signal transduction to produce lipid mediators (e.g., LTD4), cytokines [e.g., interleukin-2 (IL-2)], and matrix metalloproteinases, which participate in the pathogenesis of inflammation and autoimmune diseases.
These facts suggest that CRAC channel modulators can be useful for the treatment of diseases caused by the activation of inflammatory cells without side effects observed in steroids. Since VOC channel modulators would cause adverse events in the nervous and cardiovascular systems, it may be necessary for CRAC channel modulators to exhibit sufficient selectivity over VOC channels if they are to be used as anti-inflammatory drugs.
Accordingly, CRAC channel modulators have been said to be useful in treatment, prevention and/or amelioration of diseases or disorders associated with calcium release-activated calcium channel including, but not limited to, inflammation, glomerulonephritis, uveitis, hepatic diseases or disorders, renal diseases or disorders, chronic obstructive pulmonary disease, rheumatoid arthritis, inflammatory bowel disease, vasculitis, dermatitis, osteoarthritis, inflammatory muscle disease, allergic rhinitis, vaginitis, interstitial cystitis, scleroderma, osteoporosis, eczema, allogeneic or xenogeneic transplantation, graft rejection, graft-versus-host disease, lupus erythematosus, type I diabetes, pulmonary fibrosis, dermatomyositis, thyroiditis, myasthenia gravis, autoimmune hemolytic anemia, cystic fibrosis, chronic relapsing hepatitis, primary biliary cirrhosis, allergic conjunctivitis, hepatitis and atopic dermatitis, asthma, Sjogren's syndrome, cancer and other proliferative diseases, and autoimmune diseases or disorders. See, e.g., International Publication Nos. WO 2005/009954, WO 2005/009539, WO 2005/009954, WO 2006/034402, WO 2006/081389, WO 2006/081391, WO 2007/087429, WO 2007/087427, WO 2007087441, WO 200/7087442, WO 2007/087443, WO 2007/089904, WO 2007109362, WO 2007/112093, WO 2008/039520, WO 2008/063504, WO 2008/103310, WO 2009/017818, WO 2009/017819, WO 2009/017831, WO 2010/039238, WO 2010/039237, WO 2010/039236, WO 2009/089305 and WO 2009/038775, and US Publication Nos.: US 2006/0173006 and US 2007/0249051.
CRAC channel inhibitors which have been identified include SK&F 96365 (1), Econazole (2) and L-651582 (3).

However, these molecules lack sufficient potency and selectivity over VOC channels and hence are not suitable for therapeutic use.
Recent publications by Taiji et al. (European Journal of Pharmacology, 560, 225-233, 2007) and Yasurio Yonetoky et al. (Bio. & Med. Chem., 16, 9457-9466, 2008) describe a selective CRAC channel inhibitor coded YM-58483 that is capable of inhibiting T cell function and proposed to be of some benefit in the treatment of inflammatory diseases including bronchial asthma.

Yasurio Yonetoky et al. disclose YM-58483 to be selective for CRAC channels over the voltage operated channels (VOC) with a selective index of 31.
Other CRAC channel modulators disclosed include various biaryl and/or heterocyclic carboxanilide compounds including for example PCT or US patent applications assigned to Synta Pharmaceuticals viz. WO 2005/009954, WO 2005/009539, WO 2005/009954, WO 2006/034402, WO 2006/081389, WO 2006/081391, WO 2007/087429, WO 2007/087427, WO 2007087441, WO 200/7087442, WO 2007/087443, WO 2007/089904, WO 2007109362, WO 2007/112093, WO 2008/039520, WO 2008/063504, WO 2008/103310, WO 2009/017818, WO 2009/017819, WO 2009/017831, WO 2010/039238, WO 2010/039237, WO 2010/039236, WO 2009/089305 and WO 2009/038775, US 2006/0173006 and US 2007/0249051.
Other patent publications relating to CRAC channel modulators include applications by Astellas, Queens Medical Centre, Calcimedica and others viz., WO 2007/121186, WO 2006/0502 14, WO 2007/139926, WO 2008/148108, U.S. Pat. No. 7,452,675, US 2009/023177, WO 2007/139926, U.S. Pat. No. 6,696,267, U.S. Pat. No. 6,348,480, WO 2008/106731, US 2008/0293092, WO 2010/048559, WO 2010/027875, WO2010/025295, WO 2010/034011, WO2010/034003, WO 2009/076454, WO 2009/035818, US 2010/0152241, US 2010/0087415, US 2009/0311720 and WO 2004/078995.
Further review and literature disclosure in the area of CRAC channels includes Isabella Derler et al., Expert Opinion in Drug Discovery, 3(7), 787-800, 2008; Yousang G et al., Cell Calcium, 42, 145-156, 2007; Yasurio Yonetoky et. al., Bio. & Med. Chem., 14, 4750-4760, 2006; and Yasurio Yonetoky et. al., Bio. & Med. Chem., 14, 5370-5383, 2006. All of these patents and/or patent applications and literature disclosures are incorporated herein by reference in their entirety for all purposes.
Cancer is a major public health problem in India, the U.S. and many other parts of the world. Currently, 1 in 4 deaths in India is due to cancer. Lung cancer is the leading cause of cancer deaths worldwide because of its high incidence and mortality, with 5-year survival estimates of ˜10% for non-small cell lung cancer (NSCLC). It has been reported that further investigations on the mechanisms of tumorigenesis and chemoresistance of lung cancer are needed to improve the survival rate (Jemal A, et al., Cancer Statistics, CA Cancer. J. Clin., 56, 106-130, 2006). There are four major types of NSCLC, namely, adenocarcinoma, squamous cell carcinoma, bronchoalveolar carcinoma, and large cell carcinoma. Adenocarcinoma and squamous cell carcinoma are the most common types of NSCLC based on cellular morphology (Travis et al., Lung Cancer Principles and Practice, Lippincott-Raven, New York, 361-395, 1996). Adenocarcinomas are characterized by a more peripheral location in the lung and often have a mutation in the K-ras oncogene (Gazdar et al., Anticancer Res., 14, 261-267, 1994). Squamous cell carcinomas are typically more centrally located and frequently carry p53 gene mutations (Niklinska et al., Folia Histochem. Cytobiol., 39, 147-148, 2001).
The majority of NSCLCs are characterized by the presence of the ras mutation thereby rendering the patient relatively insensitive to treatment by known kinase inhibitors. As a result, current treatments of lung cancer are generally limited to cytotoxic drugs, surgery, and radiation therapy. There is a need for treatments which have fewer side effects and more specifically target the cancer cells, are less invasive, and improve the prognosis of patients.
The identification of lung tumor-initiating cells and associated markers may be useful for optimization of therapeutic approaches and for predictive and prognostic information in lung cancer patients. Accordingly, a need remains for new methods of predicting, evaluating and treating patients afflicted with lung cancer.
There still remains an unmet and dire need for small molecule modulators having specificity towards Stim1 and/or Orai1 in order to regulate and/or modulate activity of CRAC channels, particularly for the treatment of diseases and disorders associated with the CRAC.